JPH0267934A - Contamination preventing device for monitoring window - Google Patents

Abstract

PURPOSE:To prevent the contamination of a window and to improve reliability by providing a shutter which is opened and closed with an electromagnetic driving mechanism in front of the window, and opening the shutter only at a time required for tie monitoring of a monitoring device. CONSTITUTION:A frame 1 is attached in contact with the frame of a monitoring window 3 of a main body 2 of a monitoring device. A shutter 5 is attached to the frame 1 so as to face the monitoring window 3 is such a way that the shutter is freely opened and closed with a shaft 6. An electromagnetic driving device 7 is provided in order to drive the shutter 5. In the inside of the main body 2, fire and the like are detected based on incident radiation through the monitoring window 3. In general, time required for inputting the radiation is a fraction of one second. Time allowed for judging whether the input indicates the fire hazard into the timelength between several seconds to several tens of seconds. Therefore, a current is conducted through the device 7 only during this time period, and the shutter 5 is opened. Thus the monitoring window 3 is not contaminated, and reliability can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a device for preventing dirt on a monitoring window of a fire alarm or the like that transmits radiation such as ultraviolet rays, visible light, and infrared rays.

(B) Conventional technology In conventional sensors such as flame detectors and old lights that emit light, deep hoods are attached to the windows as a way to prevent the windows from becoming dirty as they act as entrances and exits for light. Methods such as blocking the windows and preventing dirt from being carried by the air, blowing fresh air around the windows to drive out the trash, and periodically cleaning the windows have been adopted.

(c) Problems to be Solved by the Invention The conventional method using a hood has a narrow field of view (and the method of blowing air requires a power source and also generates large particles such as mud splashed by automobiles and tires). There was a problem in that the dirt could not be blown away, and periodic cleaning required people to come and was expensive.

(d) Means for solving the problem The above problem is solved by providing a shutter in front of the monitoring window, opening and closing it as necessary, and controlling the opening and closing timing by sending and receiving signals with the main body of the monitoring device. .

(f) Function Shutters installed near the front of the window to cover the entire window are open for a short time (less than a fraction of the time they are closed), so the window can be cleaned up accordingly. In addition, without obstructing the field of view, the number of people using the vehicle can be reduced to less than a fraction.

(f) Example The present invention will be explained in detail according to the drawings.

FIG. 1 is a side sectional view showing the structure of one embodiment of the present invention.

In FIG. 1, a frame 1 is mounted in contact with the frame of a monitoring window 3 of a monitoring device main body 2, and a shutter 5 is attached to an opening 4 facing the monitoring window 3 with a shaft 6 relative to the frame 1. It is attached so that it can be opened and closed freely. 7 is an electromagnetic drive device for driving the shutter 5, which is assumed to be a rotary solenoid in the figure.

In Fig. 1, fires and the like are detected inside the monitoring device main body 2 by the radiation that enters through the monitoring window 3, but generally the time required for the radiation to enter is a fraction of a second; The time allowed to determine whether there is a fire or not is several seconds to several tens of seconds. Therefore, even if several injections are required during this period, shutter 5
The time required for the window 3 to be open and for radiation to reach the window 3 may be several minutes - or even several tens of minutes. Therefore, the electromagnetic drive device 7 is energized for this period of time to rotate the shaft 6 approximately 90'.
You can open the shutter 5 to the position indicated by the broken line, and at other times turn off the power and close the shutter 5. During the second period, the window 3 will not get dirty with dust or dirt. There is also a chance that it will get dirty with mud. The shutter 5 can also act as an eaves to prevent mud from flying in diagonally.Also, the rotary solenoid serving as the electromagnetic drive device 7 has a simple structure and only requires ON and OFF signals. It can be moved with a chisel, the drive circuit is simple, and there are few rubbing parts, making it highly durable and reliable.

FIG. 2 is a side sectional view showing the structure of another embodiment of the present invention.

In FIG. 2, a flexible film 8 with high radiation transmittance is provided between the shutter 5 and the frame 1. When the shutter 5 is closed, the film 8 is stored inside the frame 1 in a bent state, and when the shutter 5 is opened, there is a gap (tensioned) in the opening 4 as shown by the broken line. Also, this film 8 is preferably made of a resin containing fluorine, which basically has the property of being resistant to dirt.

In the embodiment with the structure shown in FIG. 2, the film 8 prevents dust from entering the window 3 while the shutter 5 is open, and the dust attached to the film 8 is removed from the film 8 as the shutter 5 opens and closes. can be screened out by being bent and stretched.

(g) Effects of the invention Dirty windows are always a big problem for sensors such as signal lights and flame detectors installed indoors and outdoors, especially outdoors exposed to wind and rain. There is an advantage that no maintenance is required to prevent dirt over a long period of time. Taking the case of a flame detector installed in a tunnel as an example,
Conventionally, several hundred flame detectors had to be manually cleaned several times a month, which was expensive and dangerous work.

However, using the device of the present invention does not require such expenses over several months (and the economic effect is not only enormous, but also cleaning work such as sensors installed at high places). It is also effective in cases where there is a lot of danger.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view showing the structure of one embodiment of the present invention;
The figure is a side sectional view showing the structure of another embodiment of the present invention.

Claims (2)

[Claims] (1) A dirty monitoring window characterized in that a shutter that opens and closes using an electromagnetic drive mechanism is provided on the front surface of the window, and the shutter is opened only during the time required for monitoring by the monitoring device, and remains closed during unnecessary times. Prevention device. (2) A flexible film with high transmittance for monitoring radiation is connected between the movable part of the shutter and the frame, and the film bends and stretches in response to the opening and closing operations of the shutter. The device for preventing dirt on a monitoring window according to claim 1.